ARM: P2V: eliminate head.S use of PHYS_OFFSET for !XIP_KERNEL
head.S makes use of PHYS_OFFSET. When it becomes a variable, the
assembler won't understand this. Compute PHYS_OFFSET by the following
method. This code is linked at its virtual address, but run at before
the MMU is enabled, so at his physical address.
Switch XIP users of PHYS_OFFSET to use PLAT_PHYS_OFFSET - we can't
use this method for XIP kernels as the code doesn't execute in RAM.
Tested-by: Tony Lindgren <tony@atomide.com> Reviewed-by: Nicolas Pitre <nicolas.pitre@linaro.org> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>